A Firefighters perspective from another forum:
"Firefighter and Driver Pump Operator here. Four inch coupling won't easily fit under a BMW sedan nor most other sedans. Second, I don't have time to feed it under. Not making that up. I do more in the first five minutes on seen pumping then the rest of the fire. When people need a continuous water supply not just the tank water, they need it right now. Third, the bend it would take to go under that car actually makes two kinks one at the hydrant and one to bend under the car that kills a lot of GPM's. Fourth, the dent in the car almost undoubtedly came from charging the line. You would be surprised by how much force a 4 inch has. They may be using 5 or 6 inch. As for him being there to move his car, sorry, no time to uncouple my hose, remove the wheel chocks, take my engine out of pump, drive around the block, come back, put it back in pump, throw my wheel chock, recouple my hose, and complete my connection. And that is assuming that they didn't pull an attack line off my truck. Then it isn't just a colossal waste of time, there is pretty much no way to say it isn't stopping the tactical objectives of command getting completed and endangering the lives of occupants or endangering exposures.
Now onto the BMW driver. He chose to park there. Those are the consequences. That hydrant and my ability to connect to it QUICKLY makes a huge difference in the outcomes of fires and the safety of my crew. You park there, knowing damn well you aren't supposed to park there, to me, it says fuck you and your crew's safety. Well...FUCK YOU TOO. I love my profession, I don't do it just for the paycheck. I work for the person that calls 911. I do this job to help people, when they need me. But to me, you parking in front of a hydrant is like spitting in my face. Just like parking in a fire lane (which I can't park in while in my engine unless I am on a call). Don't do it. Solves this whole issue."
What are the pumps connected to?
Are the two side ports the same size as the single port that the hose is hooked to? If so why?
Same guy:
"It's preconnected this way. Pull off the truck, hook up and go. Another pump comes along and hooks into both open sides of the fitting. They start pumping into one side and throw a switch on the fitting. Hydrant flow switches to the other side and into the second pump. Because the pump is so close, the plug has much less friction loss to fight and can flow better, and since the second pump is pumping way higher than static pressure, supply at the attack pump is much better. All from the same plug.
The second output only works with 2 flowing intakes though. "